Silicosis: II.—Radiology and Pathology

have a method, by means of serial X-ray examinations at different stages of the disease, of watching the pathological processes at work during life, and of correlating the findings with clinical symptoms and the degree of disability. In a case suspected, on clinical grounds, of silicosis, the two deciding points are (1) a history of exposure to silica dust, and (2) X-ray findings. Either alone is not enough. If the disease is complicated by infection, such as tubercle (as it often is) the matter becomes more difficult; but in uncomplicated silicosis in the second or third stages, as I shall point out, the X-ray appearances are fairly characteristic. Before we consider what actually occurs in the lung a brief survey of the lymphatic system of the lungs and pleura is at first necessary, since it is this system which is primarily affected in this disease. So far as we know anything about them, the following